Manufacture of unsaturated hydrocarbons.



UNITED STATES PATENT OFFICE.

FRANCIS EDWARD MATTHEWS, HENRY JAMES WHEELER BLISS, AND HARRY MONTAGUELDER, OF LONDON, ENGLAND.

MANUFACTURE OF UNSATURATED HYDROGARBONS.

Specification of Letters Patent. P t t p 1 a No Drawing. Originalapplication filed June 2 8, 1913, Serial No. 776,342. Divided andthisapplication e n filed November 25, 1913. Serial No. 803,066.

. To all whom it may concern:

.Be it known that we, FRANCIS EDWARD MATTHEWS, of 7 Staple Inn,.London,'England, HENRY JAMES \VHEELER BLIss, of Ingram House,Stockwell, London, England,

and HARRY MONT GU ELDER, of 28 Albemarle street, London, England, allsubjects of the King of Great Britain, have invented new and usefulImprovements in the Manufacture of Unsaturated Hydrocarbons, of whichthe following is a specification.

The present application is a division of our copending applicationSerial No. 7 76,34e2, filed June 28th, 1913.

In the preparation of unsaturated hydrocarbons from the halids ofhydrocarbons by abstraction of halogen acid, the methods hitherto in usehave depended upon the combinations of the acid with alkalis or bases.The decomposition of some halids, to form unsaturated bodies, by heat(for example during distillation) or by treatment With, for example,aluminium chlorid, has also been observed. It has also been proposed topass the vapors of the halids over certain contact substances such forexample as barium chlorid as a practical means of eliminating halogenacid.

We have now found that steam is a suitable and effective agent for thepreparation of unsaturated hydrocarbons from monohalids. The action ofthe steam, may, if desired, be combined With the action of catalyticsubstances. The temperature required varies according to the mono-halidused, but it should be the temperature at which the halogen acid isfreely evolved and be above that at which glycol (or un-- saturatedalcohol) is formed, while it should be kept below that at which anyconsiderable decomposition of the product occurs.

It has also been observed that some monohalids yield a proportion of anunsaturated hydrocarbon when heated with water, and that others yield analcohol, but there has been provided no satisfactory practical method ofpreparation of the unsaturated hydrocarbon in these manners.

In order to carry out'our invention we subject the mono-halid to theaction of steam ata suitable temperature, and this can conveniently beeffected by passing the vapors of the mono-halid together with steamthrough a heated tube. Or both the monohalid and water may be vaporizedtogether, the steam for the reaction being then formed in the tubeitself.

Suitable catalytic substances are those (for'example, phosphoric acid)which split off water from alcohols, or those which split ofi halogenacids, (for example, the catalysts mentioned in Meyer & J acobsen Vol.1, (1907) page 277 such as cobalt chlorid, ferrous chlorid, leadchlorid, barium chlorid,;

nickel chlorid, or copper chlorid, or the corresponding bromids orcertain other halogen compounds, particularly aluminum bromid,) but theuse of these, or any other catalysts is not as a rule required if asufiiciently elevated temperature be used.

The following are examples of how this invention can be performed, butthe invention is not limited to'these examples.

Example 1: 50 grams of hexyl chlorid (prepared by the chlorination ofhexane vapor, forinstance as described in the specificationof'application for British Letters Patent No. 13051 A. D. 1912 with, say,about 150 grams of water) are passed through a tube heated in acombustion furnace to a dull red heat. The product is condensed, steamdistilled, separated, and 'redistilled. The principal fraction obtainedis a hydro- ,carbon boiling at from 6065 centrigrade. Other monochlorhydrocarbons may be similarly treated.

Example 2: In the preparation of buta; diene from 2.3 dichlorbutanedescribed and claimed in our co-pending application forv from 600 to'700centigrade. Or its vapor may be passed through a heated tube togetherwith steam. The issuing vapors are passed through a condenser in Whichthe water and hydrochloric acid are .condensed. Any HCl remaininguncondensed maybe removed by passing the vapors through water. A gaspasses ofi which contains butadiene, with some decomposition and otherproducts. Other unsaturated mono-chlorids may be treated in a similarmanner.

The temperatures specified in theexamples are suitable for carrying outthe invention, but We do not limit ourselves to these temperatures. Ingeneral'the temperature suitable for a particular mono-halid is adjustedduring the preparation by raising the temperature until hydrochloricacid is freely evolved; which may be detected, for example bydetermining the acidity of the condensed water.

The vessels or tubes in which the process is carried out may be made ofa resistant material, for example silica.

We do not limit ourselves to any particular method of heating, which maybe external, or internal, say by means of an electric resistance.

What We claim is 1. A process of making unsaturated hydrocarbons frommono-halogen substitution derivatives of hydrocarbons including a Ichain containing the chlorin atom which comprises treating saidderivatives withsteam at a temperature at which the halogen atom isfreely evolved as hydr -hal0genic acid but which temperature is be owthat at which any considerable secondary decomposition takes place, saidtreatment being effected in the presence of a catalyst capable of aidingthe splitting ofl of halogen acid.

3.'A process of making unsaturated hydrocarbons which comprises passingmono- :lhrough a tube heated to about a dull red eat.

4. A process of making unsaturated hydrocarbons from mono-halogensubstitution derivatives of hydrocarbons including a chain containingthe chlorin atom which comprises treating them with steam at atemperature above a dull red-heat but not over about 700 C.

In testimony whereof we have signed our names to this specification inthe presence of two subscribing witnesses.

- rmcrs Emmi) imrrnrws.

111mm nuts WHEELER BLISS. mam uonr eu ELDER.

Witnesses: GILBERT FLETCHER TYAM,

VINCENT GrABDE LI.

chlor aliphatic hydrocarbons and steam

